Method and apparatus for drying gelatinous material



March 27, 1951 H. E. PECK 2,546,867

METHOD AND APPARATUS FOR DRYING GELATINOUS MATERIAL Filed March 16, 19495 Sheets-Sheet 1 A TTOR/VEY K 7 r A 7 m3 3 (2 m P n 5: 93 W R Q3 m: N Ew mm m\\ 7 w k mm mm J vv 1 mm m A9 A8 mm g)! 4\\ .3 9i t H. E. PECK2,546,867

METHOD AND APPARATUS FOR DRYING GELATINOUS MATERIAL March 27, 1951 5.Sheets-Sheet 2 Filed March 16, 1949 .K m w E m3 & m? m E U m M W N d PH:Q1 QT Q: 3 Ill' m9 n9 3? 1 w mK E but m: wwi J m E N PM L H v5 2 M i imom @Q m m m g w: n m: E q Q 1 w 91am m: a 1 W Z m? wo\ N .wm mi i A TTOR/V5 Y March 27, 1951 H. E. PEcK 2,546,867

METHOD AND APPARATUS FOR DRYING GELATINOUS MATERIAL Filed March 16, 19495 Sheets-Sheet 5 o W o 0 0\@ o INVENTOR. HENRY E. PEGK A 7' TOR/11E YMarch 27, 1951 p c 2,546,867

METHOD AND APPARATUS FOR DRYING GELATINOUS MATERIAL Filed March 16, 19495 Sheets-Sheet 5 1m EN TOR. HENRY 1:. PE 0A A TTOHNEY Patented Mar. 27,1951 METHOD AND APPARATUS FOR DRYING GELATINOUS MATERIAL Henry E. Peck,Fairport, N. Y., assignor to Me- Bean Research Corporation, Rochester,N. Y., a corporation of New York Application March 16, 1949, Serial No.81,781

13 Claims. (01. 15-4) The present invention relates to the manufactureof glue and other gelatinous products and more particularly to thedrying of animalglues and gelatins to condition them for shipment.

Gelatinous materials, such as animal glues and gelatin, are generallyextracted from the raw material in the form of solutions which are firstreduced to a jelly, and then dried to reduce the weight and bulk and toprevent deterioration of the product or growth of bacteria in theproduct during shipment. Bacteria forms in liquid glue at airtemperature.

Various methods and apparatus have been de veloped for transforming thegelatinous materials from solution into a finished dried product.

The conventional method of drying glue is to pour the glue liquor intolarge rectangular pans and to set these pans in a cold room to jell.This requires for rabbit hide glue, for instance, about twelve hours.The blocks of jelled glue are then turned out of the pans and forcedthrough a set of wires which slice the blocks into slabs- These slabsare laid out on wire netting stretched in square wooden frames. Theframes are stacked in trucks with the frames spaced apart sufficientlyfor movement of air between them; and the trucks are wheeled intotunnels throughwhich warm air is circulated to dry the slabs of'glue.Aside from the number of manual operations involved in this method thechief disadvantage lies in the slow drying rate due to the relativelysmall surface presented for drying and to the fact that the air must beblown across the product and cannot be blown through it. It requirestwelve or more hours to dry the glue in this fashion.

There have been several methods proposed for the continuous jelling anddrying of glue, butthose, with which we are familiar, involve a highcapital investment and in some cases produce an inferior grade ofproduct. Moreover, in prior types of continuous drying apparatus, thematerial has had to be stirred up more or less continu-' ously either bymen with rakes or tedders or mechanically while it is drying to preventits stickcontinuous process for jelling and drying gelatinous productsin which a batch of glue or gelatin can be dried in a relatively shortperiod. To this end, a further object of the invention is to provide aprocess for depositing jelled glue in a porous mass on a conveyer ordrying rack so that air may readily be blown through the mass to effectrapid drying.

A further object of the invention is to provide; a process for thecontinuous jelling and drying of gelatinous products which can beperformed with relatively simple apparatus and with a low capi; talinvestment.

Still another object of the invention is to provide apparatus forjelling and drying glue and other gelatinous products which isefficient, rapidin operation, and which will produce a product of veryhigh grade.

Other objects of the invention will be appar. ent hereinafter from thespecification and from the recital of the appended claims.

In the process of the present invention the glue; liquor is first pumpedthrough a heat transfer ap-. paratus. This includes a central shaftwhich ro-. tates in a cylindrical drum. On the central shaft are mountedscraper blades which scrape? the inside of the drum. The diameter of thecentral shaft is but slightlyless than that of the drum so that a' thinannular space is formed be'-. tween shaft and drum. Around the firstdrum is a larger drum forming a'second annular space through which asuitable refrigerant such as ammonia, is pumped. The central shaft isrotated at any suitable speed usually 500 to 600 R. P. M.

The glue liquor is pumped into the inner an nular chamber and becomescooled rapidly due to a thin film which is constantly formed between thecentral shaft and inner drum and which'is constantly scraped off theinner drum. The glue liquor actually becomes chilled in the heatexchanger to its jelling point but, due to the agitation of the blades,is prevented from setting into a jell until it leaves the heat transferapparatus; The subcooled liquid is forced from the heat exchanger intoan enlarged chamber, where it sets up into a jell. The jell is thenforced through a perforated extrusion plate which continuously idividesthe jell into noodles of very small diameer. truding plate is thin andhas sharp-edged orifices: The jell compresses as it passes through theholes of the extrusion .plate and then expands. The relief of thestresses causes the noodles to kink and bend. and have roughenedfractured surfaces. The noodles present therefore muchv more externaldrying area than a uniformly extruded shape would provide.

These noodles are not straight. The ex- The noodles drop from theextrusion plate onto the upper of two endless metal mesh conveyer beltswhich carry the noodles in opposite directions, respectively, through acontinuous drying chamber. Outdoor air, suitably conditioned by means ofair filters, heaters, and de-humidifying units, is "supplied. to;the,drying chamber. Each belt passes through a number ofprogressive'drying zones. In each zone hot air is passed through theglue to pick up moisture from the glue. The air is reused repeatedly.Aftenlpdfisin th fQllgh the glue in one zone it is directedthroughheaters which raise its temperature sothat whenitpasses throughthe glue again in tfienegtzpnetherelas tiv humidity is such that it willbe able to re: move additional moisture from the glue. 7

The drying air in the first zone oLdry-ingis always passed down throughthe glue and through the mesh conveyer belt. If the drying air came in 9ihebefiem. 5E354?! il 99. 2 5 .WWld 'eh an h a er al nter he. .9 veyrwould come" up to the drybulbtemperature of theair. This wouldtend'tomelt the glue. Another reason for always sending the air'down inthefirstzone is'to hold thematerial on the belt. If the air was sent upWardHnthe-firSt zone, it would tend to lift the material off the belt andscatter it. After the material has dried a little it -forms aninterlaced and bonded mass which holds itdown on the belt.

While the air goes downward in the first zone, in other zones,'the airmaybe sent upthrough the glue'to permit the material to be dried-on itsbottom so that it may readily: be stripped off the belt at the end ofthe drying operation.

The air is repeatedly re-heatedin each-oi the zones, following the firstzone, tobring it up to the maximum temperature which can safely be usedat that particular stage. in the drying-of the material. 7 the glue itdrops about. 10 to 20 due toevaporation. Each time. that the airisre-heated'itswet.

bulb temperature is .higher d'ue to the added moisture taken. upiromvthe. glue.

7 The. noodles tend to mat. as they dry, soat the end of the first beltthennoodles -.passinto -a shredder which breaks them upagain. Thesec: ndbelt travels at much. lessspeed than thesfirst belt. ;Since the materialhasbeen driedtouacon siderable. degreev in its travel on the.- firstbelt and has usually lost about 97.0% of its weight-the. ma-. terial canbe loaded ontothe. second; belt upito a much. greater thickness. than.on, the first belt.

:T-he. second .belt, like the .first .belt, travels through several heatzones. In thenextto the last,z.one, the air is-taken. out anddiscarded.:In the last zone the .air handled may. be re.-circulated. It; thematerial is still sticky.- when itreaches the. last zone the temperatureof,;the air.is.-set,high enou h. in this zoneito bake out the-glue. Ifthe material is overdry, the. moisture I content. can. be.

adjusted in this last. zone.

At 'theend of the. drying-chamber the.- material may-be continuously.discharged into .a crusher from, which it is-transferredto. binsv orotherwise treated for storage or further processing.

For rabbit; hide glue, for instance, I the. entire. drying frombeginning to-endcan be done with thev process and. apparatus of the.present. invention in approximately onehourand fortyrminutes.

the drawings:

Each time thatthe air goes. through 1 is .a. diagrammatic view inlongitudinal Fig. 2 is a vertical sectional view on a reduced scalefurther illustrating the structure of the apparatus;

Fig. 3 is a plan sectional view of the apparatus showing particularlythe upper floor of the drying chamber;

3 Fig. l is a plansectional view of the ,apparatus showing particularlythe lowerfloor ofthe dry- ,in g chamber;

- Fig. 5 is a section on an enlarged scale on the Fig, 6 .is a sectionon an enlarged scale on the Fig. 7 is a longitudinal sectional view ofthe .-heat. exchanger,.and oithe expansion chamber andeatrusion plateassociated therewith; Fig. 8 is an elevational view of the extrusion plt Fig; 9 is a transverse seetionalyiewofithe heat exchanger;

Fig. 10 is a transverse section taken orrthe-line I0l0 of Fig.7;

Fig. l1 is a diagrammatic view-efone ot-the noodles as extruded from theextrusion-plate;

12 is a diagrammatic 'vie w'showing how the noodles intertW-ineas theyare. depositeden the belt, leaving spaces. between themdorpassage of.air therethrough;

Fig. 13 is a fragmentary-planview-showing the structure of a mesh beltsuch asmay-be :used in the apparatus of the. present invention;

Fig. 14. is afragmentary planviewon an-Tene larged scale showing theshredder.. whieh:.-breaks up the materialdropping from the-firstontoathe second belt;..and

.Fig. 15 isa fragmentary vertical-sectionaltvieyv of the shredderandassociatedparts.

In the process of the presentrinyentionwglue solution ,atzaconcentration ordinarily or. %;.150. 4.0 solids is first pumpedinto. theheat exchanger or. exchangers. In the set-.up-illustrated there-are twoheatexchangers employed in .order. to; deliver enoughmaterial forthe'width of. conyeyenbelts.

used and the .speed .of. movementpf .-:those belts... The two. heat,exchangersare .identical-..=in structureqand are mountedrsideebwside.Each; iS -1d..- notedasa wholeeat 29. Since theylaresidentiealj instructure only onerneeid beedescribedi inel ltfii l Each xch n r. mprise.y n. r calriack t 2;! (Figs.;7, a .9) w h wh h s mounted acylnd rfl; teti insu a edv f om e iac t any Su tabl ns la in maienahzt. W h -tb i yid he s. m u te sses ed;yl nde i-zi.

Within the cylinder 2-! there is journaled a shait which is. ofrelatively. large .diametelfib ii'leen its ends. Securedto this sliaft;as,by-n1.e& 1 ls. of bolts 25am a plurality of, scraper' blade l.The bolts 2 6. mayjthread into. bosses, 28. med enthe. periphery of theshaft 25.

shown) to impart rotation-totheshaft;25. The

opposite end of the'shaft'25 is j'ournaled on a plain hearing or bushing34' in;the end;bearing support 35 (Figs. 7 and '10) of the-heatexchanger.

The heat eXc-l-ia-nger is closed at --one-end---by plates'36-=and-3'land-at the opposite end Icy-plates 38-:and 39'. .The plate3-] threads onto a fitting 40- that is welded or otherwise secured todrum 24. Plate 36 is secured by welding or otherwise to the drum 22. Theplate 39 is secured to plate 38 by' bolts 40 and plate 38 may be securedby welding or otherwise to the drum 22. Bearing support plate may bebolted by bolts 42 to plate39. A plate 43 serves to close one end of thespace between the drums 22 and 24. This plate may be welded to plate 38.The fitting and plate 36 close the other end of this space. Gaskets maybe provided where desirable to pre--v vent leakage. g

The gelatinous solution is pumped to the heat exchanger through pipe.45to a header 46 that is bolted or otherwise secured to plate 31. Thereduced right-hand end of the shaft'25 passes through a seal. 41 in thisheader. Cap member 3| is. bolted or otherwise secured to this header.

. Therefrigerant, which may be ammonia, may be supplied to the annularspace. between the drums 22 and 24 from the pipes 50 and 5| that threadinto a drum section 52 which is welded or otherwise secured to the drum22 andforms part thereof. The refrigerant is carried off at 0ppositeends of the annular space between drums 22 and 24 through the pipes 53and 54.

The glue solution flows from the header 46. through the narrow annularspace between the shaft 25 and the drum 24; and it is continuouslyagitated and swept off of the cold inner surface of the drum 24 by thescrapers 21 as the shaft 'rotates. The pressure of the liquid flowinginto theheader 46 from the pipe forces the glue on through the heatexchanger. In the heat exchanger, the glue is rapidly cooled down belowits jelling point because there is only a thin film of solution incontact at any time with drum 24. The glue is not allowed to set up,however, because of the agitation of the scrapers.

The sub-cooled liquid passes through the openings 56 in the end plate 35of the heat-exchanger into an adaptor 60. Thisadaptor is welded at oneend to end-plate 35 and at its opposite end to a plate 6|.

.Secured to the adaptor 69 is an extrusion noz zle 65 which isrectangular in cross-section. This nozzle tapers inwardly slightly fromits entering to its leaving end. It is welded at its right hand end to aplate 61 which is secured by bolts 53 to plate 6|. The left hand end ofthe nozzle is slabbed off and is secured by welding to a rectangula'rplate 69. The extrusion plate 15 is clamped to the plate 69 by a collarplate 12 and bolts 13.

The extrusion plate 10 is a relatively thin plate and has a plurality ofsmall holes 15 therethrough. The size and spacing of these holes, ofcourse, varies with different jobs, but in a typical installation theholes would be in diameter and spaced half an inch apart.

The adaptor 60 and nozzle 65 have cross-sections which are between and100 times the area of the passage in the heat exchanger. Hence, when thematerial comes out of the heat exchanger, the enlarged cross-sections ofthe adaptor and nozzle allow the material, which has been kept fromsetting up by the agitation of the blades in the heat exchanger, to setup. The pressure of the solution behind it forces this jelled materialon to the extrusion plate. The material comes as a solid body of ,iellthen, to the extrusion plate 10, and is extruded from the-homogeneousmass of jell into solid ribbons. If the adaptor was of the same area asthe heat exchanger, the material would be granulated in-' steadof beingformed into noodles.

6f As the jell passes through the holes in the exe trusion plate it iscompressed. As soon as it emerges from these holes, the stresses arerelieved, causing the emerging ribbons of jell to 5 kink and curl. Theslabbed delivery end of the nozzle 55 inclines the extrusion plate 10 tothe vertical as shown. The ribbons of glue drop from the extrusionplates 10 of the two cooling units then'onto a distributor (Fig. 1)Which may be 0 of any suitable construction. It may be, for, in-.stance, a small belt conveyer which is inclinedto the vertical and whichmay be made to oscillate back and forth across the line of travel ofendless belt to distribute the noodles over :the. 15 width of this belt.The weightof the material dropping from the extrusion plates breakstheribbons into noodles. such as shown at in Fig. 11. Because thematerial has been compressed in its passage through 0 the holes of theextrusion plates and then expands freely in the air after such passage,the noodles are kinked and have fractures in their surfaces, asindicated at 9| which make for more rapid drying. The size of thenoodles will vary, of course, -with the size of the holes 15 in theextrusion plate, the length of those holes, the material, etc. Forrabbit hide glue with an extrusion plate A thick and having diameterholes, the noodles 30 are about in diameter and three inches long. Theminimum ratio of the length to the diame-- ter of the noodles is aboutfive to one. The distributor fifispreads the noodles, as they; drop,over the belt 85 which is travelling at a 35 slow enough rate to allowthe desired thickness of noodles to be deposited upon it. Fig. 12 showshow the noodles deposit themselves upon the belt; intertwining with oneanother but leaving air spaces betweenthrough which the drying .air 40may pass. The noodles are deposited on the belt 85 toa thickness of oneand a half to two inches. If too great a thickness of noodles is laid onthis belt the noodles will pack down, preventing air from circulatingfreely through the material,

45 thus hindering drying.

The belt 85 carries the material into a drying chamber which in theembodiment illustrated comprises a two-story room whose side walls aredenoted at Hit and Ill (Fig. 3) and whose end so walls are denoted at H2and H3.

this room is designated l I! (Fig. 2).

The belt 85 itself is made of wire mesh so as to permit air to passfreely through it and through the material and may be of the type shownin Fig. 13. As the gelatinous material moves along with the belt 85through the drying chamber, hot air is passed through it to dry it. Theair for drying the material is first properly conditioned by 60 means ofair filters, heaters, de-huniidifying units, and washers, these unitsbeing indicatedv chamber. These frames support both the upper rollers,which carry the forward moving portion of the belt, and the lowerrollers, which carry the returning portion of the belt. In the diagram-7 5 matic views of Figs. 1 and 2, some of the rollers The roof of amass:

have-"been omittedibe'causeaofailthei smallnesstof thascale.

Partitions I I 5, which projects atfxrighti angles fromside II 9 ithe'room, I divide the aupper floor of -the drying chamber into three.drying. zones each-consisting o'f two-compartments. These compartments;are numbered 1,! 1d, '11, .lId, .III, l fidg respectively. Each of the'compa'rtmentsl, IIiand III/are input compartments. :Eachvof thecompartments 1d, IId,: .and .IIId 1 are. discharge compartments. Mountedin the compartments III-and III are heaters ltiwhichrnayibe of anysuitable aconstructi'on. Mounted in compartments' IcZ, lid an'd. IIIdare fans H6 ofanyrsuitable construction each of which im'ay beindependently motor-driven from-motors I I 8 through a pulley and beltdrive.

' f The washed, fiitered,'tie-humidified; andzheated air is dramrthrough theducis' 'IIlI and i132" (Figs. 2 an'd'3) by a motordriven'fan"'lflt whichmay be' driven by' motor IE3 through a belt and pulley drive.This fan drives the air through a .set'of heaters I05 in compartment IWhiClrheat the desiccated air up to the maximum Wet bulb temperaturewhich can: be used below-the melting point of the jellgbefore the air:passes through the mass of noodles on the belt 85.

The partitions. I I5 extend from wall H0 close tobeliLBS..Oppositeeachof the compartments I, II and'III .in the -s'et-upillustrated: there is a wall-member I20'.(F3igs.":3 and 5)=whichextendsacross the width ofiithe. compartment: between the two partitionsi I15,which define the compart-ment,aandlfrom the'fioor I Mtup t just belowtherbelt 85. Theseprevent the heatedairi from flowing in under ithebeltand-direct it, so'that it. is drawn: on byany of'ithefans lit it will godown'zthroughi the :materiat and through the belt.

.Opposite each of .thecompartments Id; lid and H111 is a partition wall1222- (Figs; 3-and-6)- which extends across the full .widtlrof.the'compartment and down fromtithe ceiling ll'lzoi'sthe room tojust'below the upper forwarding mcving' part of thebelt: 85. Thesewallsi22-preventthe1fans H6 in each of the zones Id, IId,-. ILldiiiromvdrawing the: air through the I toptof the tbelttandi compel ittoiia'aveldownwardly.

-:As'..a result of this construction, the air; after passing throughtheheaters 35 in compartment 1,. is drawn. by the fan:- I it incompartment ld down through the be1t785. Asthe air passes down throughthe-material on thebelt it picks' up moisture from the material;

5 In the drying of the glue %it is :highly'essenti'al that the wet bulbtemperature at the inlet'of any drying zone should not exceed themelting point. of the glue; otherwise the glue would form into a'solidblo'ck throughuwhich' it -would' be impossible to blowair. "As thedry air=comes into contact with the noodles, however, a skin-01"relatively drymaterial:isiormed on the noodles giving them strengthendugh to sustain themselves. As the glue dries; then;'it wilt-withstandhigher temperature; whichi'will, of. course, promote more rapididrying.:The-air- .will be cooled, ofcourse, in going through the bed of glue sothat itwill be approximately at the wetibulb' temperature after itspassage therethrough. Thereby there is no tendency to melt the partofthe'glue which is in contactxwith the conveyer.

After: passage of the air. throughzthe material inthefirst'zone oftravel oirbeltrBt, thefimoistsair is drawn from below the-belt $5,?vbyttheziani I Hi imcompartment- Id,,;discharged through anfopening I 24(similarto that shcwir in Figrfifi'inlthe 8- Ieftehandi; partition-"wall:I I5 zof mzonei Idmazid driven; through: az second group. of theatersit 5 compartment II. zi'lz'h'eseiheaters, whichzaresetat a ahigherltemperature than the: heaters I05 bf compartment I, raise i thetemperature :of ,the moisture-laden air. The vfan I I 6 in compartmentIIcZ pulls-the: further-heated air down through the :material. and; downthrough the: belt; again and under "the-belt 85 asatherbeltmovespastcompartment. Ildpandzdrives. the air :intola third setizof ih'eatersilll51in compartment'III. the air passes through the material it, offcourse, pickssup further moistureufrom thermateriahand dries it'stilhmore. The temperaturezofithenfcis-I ture -laden-. air. is stillfurther raisedby the-heaters in: compartment .HI. The. further-eheatedlair: sis drawn'rfrom'the heaters down through: thee-belt againzby. fan.I I6 rint compartment. II-Id. Itagain. picks. uprmoisture' from'theimaterialaand'further dries the-material.

.The belt SBimay'be of" any desirablelengthand. itzma.travelqatanydesirable speed. In -a typical installation for dryingrabbit hide glue a belt? 85 is -zemployed :thatis sixty feet long andathat travels at. ther-rate-of: three: feet: per minuterso that it takesthezm'aterial' on thebeltonly twenty minutes to travel the length of.the-upper floor-of the drying chamber and be "subjected: tozthreesuccessive drying treatmeirts whilexpassing opposite zones 1; II, andIII.

,Thegluaas' itdries tendsitomat; Suatfthfififld of the belt 85,:thezmatsofznoodles" are :passd through a shredder whichrbreaks up: thesezmatsl'I'hlS'ShIQddBIZmayFIGET of any suitable construc- As shown it'comprisesaa rotating; knife I30 (Figs. 14; and.15)havinga'plurality'nfrbiades I31 arranged aboutand along its axis. ..,The;lmife:is securedto a shaft I32 whichmay be drivenun any suitable manner. Thebladesofthexkiiifeeare adapted to; pass between fingers: or prongsl 134that: arewelded oriotherwisesecured to abracket iilt'wnich is mountedronone of the .crossbeams of the building. "The mats of partially driedglue drop on of the belt 85 onto a. downwardly inclined'defiector plateI31 wliich:is welded tcithe prongs I34. :A'scrapenplate'I38rmaybeiwelded to the deflector plate I 37; tcr-p'reventthe'gluez-fronr being carried around with the belt.

The shredded material dropsthrou'gh the'grata which is formed. by:fingers lSQsonto a lowersbejlt MO-which rides over'rollers 'I M=This2b'elt travels in the. reverse direction to: thei ibeltB'Jaandzaat. slower-speed, preferablyiatabout halithe speed. of belt-35. Of course, due to the slower speed. of travel of belt I453themateriallwillxpileupshigher on belt I49 than onibeltnflli. ssince thematerial has been dried to a considerable degree -inliits travel ;on:belt 85, ihOWVBl,5iand has ilost about of its weight,- and :has,:moreover 'a hard outer coating, it canbe loaded on theElcwenbelt I40 toa much greater thickness Without matting; AsaneXampleYthe material maybe laid to za thickness of one anol' a half to two inches on the beltand to a thickness of 'four inches or more on the belt I40.

'The belt I40 trav'elsthe length of the lower floor of the'idryingchamber andmay beof the same length as be1t'85. The- 1ower floor of thechamber is divided like the upper fioorinto s-ix compartments denotedIVjIVd, V, Vd,"VI,- and VId, respectively. Partition walls I 15 whichextend at'right angles to the wall Iii! of the build ing close to' thebelt I40- separate thesecomparm ments. Thecompartments I'Vf V and VIare'inl'et compartments vand thewcompartments IVd,"V'd,

VId are outlet compartments. Mounted in the inlet compartments IV, V,and VI are sets of heaters I05. Mounted in the discharge compartments Ndand Val are fans H6; and mounted in the discharge compartment VId is asomewhat smaller fan I I. 1

' Opposite each of the inlet compartmentsIV, V and VI is a partitionwall I46 (Figs. 4 and 6) which extends down from the ceiling H4 to justbelow the belt I40. Opposite each ofthecompartments IVd, Vd, and VId isa partition wall I48 which extends up from the floor I41 of the room tojust below the top of the belt I40.

.- By the time the noodles have reached the lower belt I40 they aresufficiently dry that there is no longer any tendency for the material,which is in contact with this conveyer belt, to melt. It is desirable,however, to insure that this material contacting the belt is thoroughlydry at the end of the drying operation so that it may readily bestripped from the belt. For this purpose the direction of flow of theair through the material may be reversed on the lower drying floor. Itmay be sent up through the belt I40 and up through the material insteadof down.- The direction of flow of the air in any zone of the dryingchamber is simpl a matter of location of the partitions I20, I22, I46and I48. In the first zone, zone I, however, the air flow should bedownwardly through the material and the belt, for the reasons alreadygiven.

The moisture-laden air that is drawn through the material by the fan N5of upper compartment 11101 is driven by that fan into a duct I25 whichdelivers it to the set of heaters I05 in lower compartment IV. Itstemperature is raised by these heaters; and it is drawn by the fan H6 incompartment IVd up and through the mass of material on the belt I40. Itpicks up further moisture from the material and further dries thematerial. Then it is forced by thefan H6 in compartment IVd throughheaters I05 in compartment V, where its temperature is further raised.Then it is drawn by the fan IIfi'in compartment Vd once more up andthrough the material, picking up further moisture from the material andfurther drying the material.

By this time, the air is at or near its saturae tion point. So it isdischarged by the fan IIIS of compartment Vd into a duct I49 that leadsto the outside air.

In the sixth zone comprising compartments VI and VIcZ, final drying maybe effected by recirculation of air in a substantially closed system.There are a set of heaters I05 in compartment VI and a fan Iit incompartment VId. The fan H6 is mounted in reverse position from the fanof compartments IVd and Val. This fan IIB' draws air up through the beltI40 and the material thereon into compartment VIcZ and forces thiair-through the set of heaters I05 in compartment VI out under partitionI40 whence it is again'drawn by the fan up and through'the belt and thematerial. Dampers I (Fig. 3) are providedin the floor H4. These can beopened or closed manually and independently of one another. .I'hereby,moist air may be drawn in from zoneI to the recirculating system, or airmay be discharged from the recirculating system into the main dryingsystem. Complete control of the temperature and moisture-content of theair in the recirculatingsystem in the sixth zone is therefore possiible.If the material is still sticky when it reaches this zone, it cantherefore be baked out by heating the air toa high temperature lf 10 thematerial is overdry, the moisture content can be adjusted. v I Bydriving the air-'up through the material from below in the last' zone orzones, the material contacting the belt can be dried so that it willfreely leave the belt. This permits the material to be stripped off thescreen mesh of the belt easier. 1

When the material reaches the end of the bel I40, it drops onto a beltI60 (Fig. 1) which is supported by rollers I6I. Belt I60 may carry thenow-dried material to a crusher from which it may be transferred intobins or otherwise treated for storage or for further processing. 1

From the preceding description it will be seen that with the process andapparatus of the present invention it is possible t'o-dry glue in a;very short time, automatically, with a: minimum of attention, and withsimple, relatively inexpensive equipment. The product is completelyenclosed in highly sanitary surroundings during chilling and jellingfrom which 'air is completely ex:- cluded. Chilling and jelling areextremely rapid, minimizing the effect of destructive bacterial actionduring this stageof the process. The chilling and jelling"apparatusitself, moreover, is easily cleanable and occupies a very'small space.

In the drying operation, 'all'new or outdoor air, properly filtered anddesiccated to therequired moisture content (approximately grains ofmoisture per pound of air) is used.

The gelatin'as it leaves the extrusion plates is in extremely dri'ableform having a surface area, for rabbit hide glue, for instance, inexcess'of 10 sq. ft. per pound of material and is loosely knittedtogether so that drying air can be passed through the entire mass; Thefact that We 'are able to blow air through the mass rather'than acrossthe top of it or the bottom of it enables us to dry large quantities ofthe glue in a relatively short time-with a minimum of air flow.

The entire'volume of air is discharged at the end of the main dryingsection just ahead of the final tempering zone. The air is dischargedwith a very high moisture content corresponding to the highest wet bulbtemperature that the material can safely stand'in its final dryingstage, resulting in very economical drying. This process of dryinggelatinous materials has several advantages'over other methods. The veryrapid drying greatly reduces the danger of bacterial growth andcontamination. The high ratio of surface area to volume of the gelatinin the noodle form and the effective utilization of this drying area inthe drier construction permit large drying capacity in a relativelysmall space and with a high thermal efiiciency-p The progressivereheating air circuits permit the maximum utilization of a minim-um ofnew outdoor air and the air has only to be desiccated once at thebeginning of the cycle, resulting in a minimum ofair-conditioningequipment as compared to other continuous driers. Air isdischarged from the drier carrying more moisture than the wettestoutdoor air in summer, eliminating any need for uneconomical redryingfor recirculation. The manpower requirements of the drier, moreover,-are very low as compared to practically all other drying methods; Withthe present apparatus the smallest possible quantity of air is used withthe lowest possible moisture content and the air iscontinuously reused.The air starts with forty grains of moisture per pound of air-and endsupdisposed along the length of said conveyer adjacent said conveyer, meansfor supplying air to the compartment nearest the inlet end of thechamber, heaters for heating air and fans for circulating air mounted inalternate compartments, the walls of said compartments which areadjacent the conveyer only partially closing compartments whereby aircan circulate between the compartments and the part of the chambercontaining the conveyer, and means for driving said fans to cause theair to travel longitudinally through the chamber from the inlet end tothe discharge end thereof and to pass repeatedly epthwise through thematerial on the conveyer as the material travels on the conveyer fromthe inlet end to the discharge end of the chamber, successive heatersbeing arranged to raise progressively the temperature of the air as theair travels through the chamber, whereby the air is at its lowesttemperature at the inlet end of the chamber and at its highesttemperature at the discharge end of the chamber.

11. Apparatus for drying gelatinous material omprising a drying chamberhaving an upper and a lower floor, each floor'being provided with aplurality of compartments arranged along its length that are partitionedoii from one another, a foraminous belt running the length of eachfloor, the lower belt running in the opposite direction to the upperbelt and at less speed than the upper belt, and being positioned toreceive material from the upper belt at the end of the travel of thatbelt, means for supplying desiccated air of low moisture content to thefirst compartment on the upper floor, heaters in alternate compartmentsof the two floors for heating the air, fans in the other compartments ofthe two floors for forcing the air depthwise through the material as ittravels along on the belts, means for directing the air after itsrepeated passage through the material on the upper down to the loweriioor so that it may be reused and passed through the material as ittravels on the lower belt.

12. Apparatus for drying gelatinous material comprising a drying chamberhaving an upper and a lower floor, each floor being provided with aplurality of compartments arranged along its length that are partitionedoff from one another, a foraminous belt running the length of eachfloor, the lower belt running in the opposite direction to the upperbelt and at less speed than the upper belt and being positioned toreceive material from the upper belt at the end of the travel of theupper belt, heaters in alternate compartments of the two floors, fans inthe other compartments of the two floors, means for supplying desiccatedair of low moisture content to the first compartment on the upper floor,means for actuating the fans of the upper floor to force the air firstthrough the heaters and then depthwise through the material as it movesalong the length or the upper floor with the upper belt, a shredder atthe end of the upper belt into which the material drops off that belt,means for operthe shredder to break up the material beiore it falls onthe lower belt, the next to the last fan on the lower floor beingarranged to discharge the air from the drying chamber, and the last fanon the lower floor being arranged to circulate air in a substantiallyclosed system through the material as it travels with the lower beltpast the last two compartments.

13. The method of processing gelatinous material which comprises formingliquid gelatinous material into jelled ribbons, depositing the ribbonein a gas-permeable mass on a longitudinally-traveling conveyer, passingair repeatedly through the material depthwise of the material as thematerial travels longitudinally with the conveyor, and repeatedlyraising the temperature of the air after passage through the materialand prior to another passage through the material to d the material, theair being directed to travel between its successive passages through thematerial. in the same direction as the material whereby the air is oflowest temperature when it makes its first passage through the materialand is of highest temperature when it makes its last passage through thematerial.

HENRY E. PECK.

REFERENCES CITED The following references are of record in the "file ofthis patent:

UNITED STATES PATENTS Number Name Date 473,263 Proctor Apr. 19, 1892681,229 Kelsey Aug. 2'7, 1901 797,276 Glauser Aug. 15, 1905 1,312,607Baetz Aug. 12, 1919 1,547,294 Braemer July 28, 1925 1,551,818 GarnseySept. 1, 1925 1,744,884 Greiner Jan. 28, 1930 1,751,552 Kehoe Mar. 25,1930 1,813,750 Mackensie July '7, 1931 1,822,313 Quiggle Sept. 8, 19311,906,694 Lowry May 2, 1933 1,980,898 Abernethy Nov. 13, 1934 1,981,806Lowry Nov. 20, 1934 2,142,568 Lowry Jan. 3, 1939 2,216,188 Dons et a1Oct. 1, 1940 2,280,704 Hurxthal Apr. 21, 1942 2,339,979 Clarke Jan. 25,1944 FOREIGN PATENTS Number Country Date 555,034 Great Britain July 30,1943 OTHER REFERENCES Aero-Form Drying," published by Proctor andchwartz Inc, 25 pages. Received in Div. 49, April 13, 1936 (copy in34-223).

5. THE METHOD OF PRODUCING GELATINOUS MATERIAL WHICH COMPRISES COOLING A SOLUTION OF THE MATERIAL TO THE JELLING POINT OF THE SOLUTION IN A COMPLETELY ENCLOSED CHAMBER FROM WHICH AIR IS EXCLUDED WHILE AGITATING THE SOLUTION TO PREVENT IT FROM JELLING, FORCING THE SUB-COOLED SOLUTION INTO AN ENLARGED CHAMBER FROM WHICH AIR IS ALSO EXCLUDED, ALLOWING THE SOLUTION TO JELL IN SAID ENLARGED CHAMBER, THEN EXTRUDING THE JELL FROM THE CHAMBER IN RIBBONS, COLLECTING THE EXTRUDED MATERIAL AND PASSING HEATED AIR DEPTHWISE THROUGH THE MATERIAL TO DRY THE MATERIAL.
 8. THE METHOD OF DRYING GELATINOUS MATERIAL WHICH COMPRISES COOLING A SOLUTION OF THE MATERIAL TO THE JELLING POINT OF THE SOLUTION WHILE AGITATING THE SOLUTION TO PREVENT IT FROM JELLING, FORCING THE SUB-COOLED SOLUTION INTO AN ENLARGED CHAMBER TO PERMIT IT TO JELL, EXTRUDING THE MAMATERIAL IN RIBBONS, COLLECTING THE EXTRUDED MATERIAL ON A TRAVELING FORAMINOUS CONVEYOR, PASSING HEATED AIR REPEATEDLY THROUGH THE MATERIAL DEPTHWISE OF THE MATERIAL AS IT MOVES ALONG WITH THE CONVEYOR, AND RAISING THE TEMPERATURE OF THE AIR AFTER EACH PASSAGE THROUGH THE MATERIAL PRIOR TO THE NEXT PASSAGE OF THE AIR THROUGH THE MATERIAL, THE AIR BEING PASSED DOWN THROUGH THE MATERIAL AT LEAST ON ITS FIRST PASSAGE THROUGH THE MATERIAL AND THE AIR BEING PASSED UP THROUGH THE MATERIAL AT LEAST ON ITS LAST PASSASGE THROUGH THE MATERIAL. 